Animation

Moving pictures add life to a static scene. This section describes the various techniques used to create animation.

Movies

The simplest animation method is to create a movie. Like a movie in the cinema, these have a set of frames that are displayed one after another. These movies can be stored in many different formats, such as animated GIF files and MPEG (Motion Picture Expert’s Group format).

A useful feature of many file formats is streaming. A streamed movie can be displayed from the web as it is being downloaded, and does not require the whole movie to be downloaded before playback can commence. Streaming also handles streams that suffer a break during transmission, and it is also possible to join a stream after it has commenced playback. The premier format for streamed video is MPEG.

Per-Vertex Vector Animation

This can be used with vector graphics, to specify the picture at each frame of the animation by specifying the position of the descriptive coordinates at each point. This is the same as putting together a sequence of vector graphic pictures, and displaying them one after another. In the same way as vector graphic files can be much smaller than pixel graphic files, so vector animations are usually much smaller than pixel-based movie files. Most Macromedia Shockwave files use this type of animation.

3D Virtual Reality Modeling

Using VRML, it is possible to create 3D scenes that have dynamic, time dependant behavior. This type of dynamic 3D is very much in its infancy, and we can expect great advances in this area with the next generation of VRML. However, it is already possible to generate an impressive amount of animation in a real time rendered VRML world. The specification of this type of animation lends itself to simple, repetitive or event occasioned movement.

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